If you do it after they've left, not only are they not an intruder any more, but you are seeking revenge rather than stopping a threat. In that case, I'd guess a jury would say, "We have two scumbags--the former intruder and this guy with a gun. The home invader is dead so one problem is solved, now let's put the shooter in jail and solve another."

I know this is an old inactive topic, but our current government is changing the landscape to favor the person(s) who has to react to home invasions. Current bills in government (not yet ascended, thus not law yet) had drastically simplified the text to favor the person committing the act of defense.

A Nunavut man who fired a semi-automatic rifle at five people breaking into his home, killing three and wounding two, has had his murder convictions overturned.In a strong defence of self-defence, a panel of appeal court judges declared a self-defence claim can be made even when three of the dead were shot in the back — one while wounded on the ground — and two who survived were shot while running away.Although not calling it justified, the Nunavut Court of Appeal accepted that self-defence was a plausible defence that was tainted by the trial judge’s rulings on what evidence the jury was allowed to hear.The appeal court ordered a new trial.The dramatic shooting in January 2007 rattled Cambridge Bay, a hamlet of 1,500 best known as a way station along the Northwest Passage.A feud between young men culminated in a confrontation at the small house of Chris Bishop, 27. At 3 a.m. Mr. Bishop called the RCMP saying men were trying to break in.Long before help arrived, his front door started to give way to the kicking, and he retreated to his bedroom. He readied a gun.He held what is called an SKS-D, which he legally owned. The semi-automatic rifle is supposed to hold only five bullets but Mr. Bishop fitted it with a 25-bullet “banana clip,” an illegal add-on that gives it a similar appearance to an AK-47.

"In a strong defence of self-defence, a panel of appeal court judges declared a self-defence claim can be made even when three of the dead were shot in the back — one while wounded on the ground — and two who survived were shot while running away......"